Authentication through tissue-conducted sound

ABSTRACT

Systems and methods may provide for sending a sound wave signal and measuring a body conduction characteristic of the sound wave signal. Additionally, a user authentication may be performed based at least in part on the body conduction characteristic. In one example, the body conduction characteristic includes one or more of a timing, a frequency or an amplitude of the sound wave signal after passing through one or more of bone or tissue.

TECHNICAL FIELD

Embodiments generally relate to user authentication. More particularly,embodiments relate to user authentication through tissue-conductedsound.

BACKGROUND

Authentication may be used to grant or deny user access to varioussystems such as, for example, electronic commerce (e-commerce) systems,consumer devices, online accounts, and so forth. While traditionalauthentication approaches may have involved user entry of login and/orPIN (personal identification) information, more recent solutions mayevaluate biometric information such as fingerprint, retina and/or voicescans submitted by the user. Each of these approaches may involve activeparticipation on the part of the user (e.g., PIN entry, fingerprintswipe, voice prompt responses). Accordingly, conventional solutions maybe inconvenient and/or bothersome to the user. Moreover, these solutionsmay be unsuitable in situations when user awareness of theauthentication process is not desired and/or the user is notawake/unconscious.

BRIEF DESCRIPTION OF THE DRAWINGS

The various advantages of the embodiments will become apparent to oneskilled in the art by reading the following specification and appendedclaims, and by referencing the following drawings, in which:

FIGS. 1A and 1B are illustrations of examples of form factors foruser-based systems according to embodiments;

FIG. 2 is a flowchart of an example of a method of authenticating usersaccording to an embodiment;

FIGS. 3A and 3B are flowcharts of examples of methods of training andoperating, respectively, an authenticating apparatus according to anembodiment;

FIG. 4 is a block diagram of an example of an authentication apparatusaccording to an embodiment;

FIG. 5 is a block diagram of an example of a processor according to anembodiment; and

FIG. 6 is a block diagram of an example of a computing system accordingto an embodiment.

DESCRIPTION OF EMBODIMENTS

Turning now to FIG. 1A, a user-based system 10 is shown in which userauthentication is performed through tissue-conducted sound. In theillustrated example, the system 10 generally has a substantiallysingle-part enclosure with a headset form factor and one or more tissueconduction speakers (e.g., in contact with the skin, not shown) thatproduce sound wave signals 12. Alternatively, air speakers may be usedto generate the sound wave signals 12, although tissue conductionspeakers may be more efficient, depending on the circumstances. Thesound wave signals 12 may propagate through the bone and/or tissue inthe head of a wearer 14 of the system 10, wherein the propagated soundwave signals 12 may be captured by one or more sensors (e.g., tissueconduction microphones) and analyzed to detect and/or identify thewearer 14. For example, body conduction characteristics such as, forexample, the timing, frequency and/or amplitude of the propagated soundwave signals 12 after passing though bone and/or tissue may be analyzedas part of the user authentication process.

The sound wave signals 12 may be configured based on (e.g., tailored to)an expected user (e.g., in accordance with a previous training processand/or user preference/profile) and may be transmitted as pulses orother suitable waveform. For example, it may be determined that somewaveforms are more effective than others for a particular user (e.g.,based on the size of the person). Moreover, certain users may havepreferred wearable device configurations that may be taken intoconsideration when tailoring the sound wave signals 12 to the expecteduser. Additionally, the sound wave signals 12 may be either audible orinaudible from the perspective of the wearer 14. Configuring the soundwave signals 12 as inaudible/imperceptible signals may enable the userauthentication to be conducted without the awareness of the wearer 14.In one example, the signals 12 are incorporated into music or otherpre-existing audio signal being output to the wearer 14. As will bediscussed in greater detail, the illustrated approach may be used inconjunction with additional authentication factors such as, for example,voice input, gesture input or textual input.

Other headwear form factors such as, for example, glasses, hats,headbands, etc., may be used for the system 10 depending on thecircumstances. Moreover, other non-wearable or wearable form factorssuch as, for example, wrist wear form factors, hand wear form factors,may be used for the system 10. For example, FIG. 1B shows a user-basedsystem 16 (16 a, 16 b) that includes a multi-part enclosure having afirst portion 16 a with a wrist wear (e.g., watch, bracelet) form factorand a second portion 16 b with a hand wear (e.g., ring) form factor. Inthe illustrated example, the first portion 16 a includes one or moretissue conduction speakers that produce sound wave signals 18, whereinthe sound wave signals 18 propagate through the bone and/or tissue inthe hand 20 of a wearer. The propagated sound wave signals 18 may becaptured by one or more sensors (e.g., tissue conduction microphones,accelerometers) and analyzed (e.g., based on timing, frequency,amplitude) to detect and/or identify the wearer.

For example, the amplitude of a sound wave may vary by the mass of thetissue through which it traverses. Accordingly, that variance may beused to discriminate across wearers. Other variations of characteristicsacross bodies, such as, for example, shape and density of tissue mayalso affect how sound waves conduct through tissue. For example, sometissues of certain thickness and density may conduct high frequencysound waves better than others. Additionally, wearer identity may be afunction of how certain patterns of sound waves (e.g., pulseconfiguration) propagate through tissue. In another example, the secondportion 16 b might have the form factor of a smart phone, tabletcomputer or other handheld device containing one or more accelerometerscapable of detecting the vibrations of the hand 20 whilegrasping/squeezing the second portion 16 b. Variations on placement ofthe second portion 16 b include, but are not limited to, anklebracelets, shoes and other items worn on the limbs of a user.

Turning now to FIG. 2, a method 22 of authenticating users is shown. Themethod 22 may be implemented as a module or related component in a setof logic instructions stored in a machine- or computer-readable storagemedium such as random access memory (RAM), read only memory (ROM),programmable ROM (PROM), firmware, flash memory, etc., in configurablelogic such as, for example, programmable logic arrays (PLAs), fieldprogrammable gate arrays (FPGAs), complex programmable logic devices(CPLDs), in fixed-functionality hardware logic using circuit technologysuch as, for example, application specific integrated circuit (ASIC),complementary metal oxide semiconductor (CMOS) or transistor-transistorlogic (TTL) technology, or any combination thereof. For example,computer program code to carry out operations shown in method 22 may bewritten in any combination of one or more programming languages,including an object oriented programming language such as Java,Smalltalk, C++ or the like and conventional procedural programminglanguages, such as the “C” programming language or similar programminglanguages.

Illustrated processing block 24 provides for sending a sound wave signalvia, for example, a tissue conduction speaker in contact with the skinof a user. One or more body conduction characteristics of the sound wavesignal may be measured at block 26. The body conduction characteristicsmay include, for example, timing (e.g., propagation delay), frequency(e.g., center frequency, harmonics), amplitude (e.g., attenuation), andso forth, relative to bone (e.g., cranium, phalanges), tissue (e.g.,connective/cartilage, muscle, nervous, epithelial), etc., or anycombination thereof. Illustrated block 28 performs a user authenticationbased at least in part on the body conduction characteristic(s). Asalready noted, performing the user authentication may include detectinga user, identifying the user, and so forth. Moreover, the userauthentication may be performed further based on an additionalauthentication factor including voice input, gesture input, textualinput, etc., or any combination thereof. In one example, block 28includes capturing, via one or more of a tissue conduction microphone oran accelerometer, a measurement signal associated with the sound wavesignal and comparing the measurement signal to a previously acquiredtraining signal.

FIG. 3A shows a method 30 of training an authentication apparatus. Themethod 30 may be implemented as a module or related component in a setof logic instructions stored in a machine- or computer-readable storagemedium such as RAM ROM, PROM, firmware, flash memory, etc., inconfigurable logic such as, for example, PLAs, FPGAs, CPLDs, infixed-functionality hardware logic using circuit technology such as, forexample, ASIC, CMOS or TTL technology, or any combination thereof.

In the illustrated example, the user puts on a system containing theauthentication system and the system sends one or more test pulses,wherein block 32 provides for sending test pulses of varying timing,amplitude, and frequency of vibration waves through the body of theuser. One or more tissue conduction microphones may pick up (e.g.,sense, measure) the pulses propagating through the body at block 34.Block 36 may determine (e.g., via a machine-learning component) anexpected timing, amplitude and frequency of received waves from the userin question. Optionally, a voice prompt may be sent to the user at block38, wherein a voice response may be received at block 40. The voiceresponse may be received via tissue conducting and/or air conductingmicrophones. Illustrated block 42 characterizes the voice of the userbased on the voice response. Other authentication factors such as, forexample, gesture input and/or textual input may also be used to trainthe authentication apparatus.

FIG. 3B shows a method 44 of training an authentication apparatus. Themethod 44 may be implemented as a module or related component in a setof logic instructions stored in a machine- or computer-readable storagemedium such as RAM ROM, PROM, firmware, flash memory, etc., inconfigurable logic such as, for example, PLAs, FPGAs, CPLDs, infixed-functionality hardware logic using circuit technology such as, forexample, ASIC, CMOS or TTL technology, or any combination thereof.

In the illustrated example, a user action initiates an authenticationrequest, wherein block 46 provides for sending pulses from one or moretissue conducting speakers. The pulses may be received via one or moretissue conducting microphones at block 48 and a determination may bemade at block 50 as to whether the timing, amplitude and/or frequency ofthe received pulses meets an expected target (e.g., for a particularuser). If it is determined at block 52 that the expected target is met,illustrated block 54 sends a voice prompt to the user. A user responseto the voice prompt may be received at block 56, wherein illustratedblock 58 provides for analyzing the voice response in terms of voicequality and content. If it is determined at block 60 that an expectedtarget is met, access (e.g., to an e-commerce system, consumer device,online account, etc.) may be granted at block 62. If either the soundwave pulses or the voice prompt do not meet the expected target, accessmay be denied and the method 44 may terminate at block 64.

Thus, the illustrated approach may use tissue conduction as a passiveprecursor to other higher level authentication techniques involvingactive user participation. As a result, power efficiency may beimproved. Additionally, the tissue conduction pulses may be sentperiodically, wherein only if the passive tissue conductionauthentication fails for a specific period of time, would more explicitvoice-based authentication be used. The periodicity of the passivetissue conduction authentication may also be changed dynamically basedon the user, device and/or environmental context.

Turning now to FIG. 4 an authentication apparatus 66 (66 a-66 c) isshown. The apparatus 66 may generally implement one or more aspects ofthe method 22 (FIG. 2), the method 30 (FIG. 3A) and/or the method 44(3B), already discussed. In the illustrated example, an outbound signalcontroller 66 a configures a sound wave signal based on an expected userand sends the sound wave signal via a speaker 68, wherein an inboundsignal controller 66 b measures a body conduction characteristic of thesound wave signal. For example, the inbound signal controller 66 b mayinclude a sensor interface 70 to capture, via a sensor 72 (e.g., airmicrophone, tissue conduction microphone, accelerometer), a measurementsignal associated with the sound wave signal and compare the measurementsignal to a training signal. The body conduction characteristic mayinclude a timing, frequency and/or amplitude of the sound wave signalafter passing through one or more of bone or tissue.

The illustrated authentication apparatus 66 also includes anauthenticator 66 c to perform a user authentication based at least inpart on the body conduction characteristic. In one example, theauthenticator 66 c includes a presence detector 74 to detect a user(e.g., distinguish between the presence or absence of a user) and arecognizer 76 to identify the user (e.g., distinguish between aparticular user and other users). The illustrated authenticator 66 calso includes a supplemental factor component 78 to perform the userauthentication further based on an additional authentication factorincluding one or more of voice input, gesture input or textual input.

For example, in the case of a wrist-worn system, the user might beprompted to make a particular hand gesture (e.g., motion hand upward, tothe left, to the right, etc.) that may be monitored via one or moreaccelerometers or other suitable sensors. Indeed, the supplementalfactor component 78 may provide for multiple authentication factors tosupplement tissue conduction. Thus, one supplemental factor may be ahand gesture that is input via a smart phone and another supplementalfactor may be a foot gesture that is input via a shoe-worn device,wherein a positive result from all three factors (e.g., tissueconduction, hand gesture, foot gesture) might be required before accessis granted.

Additionally, the authentication apparatus 66 may be contained withinthe same platform (e.g., single-part enclosure) as in case of theuser-based system 10 (FIG. 1A) or distributed across multiple platforms(e.g., multi-part enclosure) as in the case of the user-based system 16(FIG. 1B). Moreover, the platforms may collaborate (e.g., using a bodyarea network (BAN) to determine the most appropriate set of devices toparticipate in the authentication.

FIG. 5 illustrates a processor core 200 according to one embodiment. Theprocessor core 200 may be the core for any type of processor, such as amicro-processor, an embedded processor, a digital signal processor(DSP), a network processor, or other device to execute code. Althoughonly one processor core 200 is illustrated in FIG. 5, a processingelement may alternatively include more than one of the processor core200 illustrated in FIG. 5. The processor core 200 may be asingle-threaded core or, for at least one embodiment, the processor core200 may be multithreaded in that it may include more than one hardwarethread context (or “logical processor”) per core.

FIG. 5 also illustrates a memory 270 coupled to the processor core 200.The memory 270 may be any of a wide variety of memories (includingvarious layers of memory hierarchy) as are known or otherwise availableto those of skill in the art. The memory 270 may include one or morecode 213 instruction(s) to be executed by the processor core 200,wherein the code 213 may implement the beacon blocks or the observationblocks of the method 22 (FIG. 2), the method 30 (FIG. 3A) and/or themethod 44 (FIG. 3B), already discussed. In one example, the memory 270is non-flash memory. The processor core 200 follows a program sequenceof instructions indicated by the code 213. Each instruction may enter afront end portion 210 and be processed by one or more decoders 220. Thedecoder 220 may generate as its output a micro operation such as a fixedwidth micro operation in a predefined format, or may generate otherinstructions, microinstructions, or control signals which reflect theoriginal code instruction. The illustrated front end portion 210 alsoincludes register renaming logic 225 and scheduling logic 230, whichgenerally allocate resources and queue the operation corresponding tothe convert instruction for execution.

The processor core 200 is shown including execution logic 250 having aset of execution units 255-1 through 255-N. Some embodiments may includea number of execution units dedicated to specific functions or sets offunctions. Other embodiments may include only one execution unit or oneexecution unit that can perform a particular function. The illustratedexecution logic 250 performs the operations specified by codeinstructions.

After completion of execution of the operations specified by the codeinstructions, back end logic 260 retires the instructions of the code213. In one embodiment, the processor core 200 allows out of orderexecution but requires in order retirement of instructions. Retirementlogic 265 may take a variety of forms as known to those of skill in theart (e.g., re-order buffers or the like). In this manner, the processorcore 200 is transformed during execution of the code 213, at least interms of the output generated by the decoder, the hardware registers andtables utilized by the register renaming logic 225, and any registers(not shown) modified by the execution logic 250.

Although not illustrated in FIG. 5, a processing element may includeother elements on chip with the processor core 200. For example, aprocessing element may include memory control logic along with theprocessor core 200. The processing element may include I/O control logicand/or may include I/O control logic integrated with memory controllogic. The processing element may also include one or more caches.

Referring now to FIG. 6, shown is a block diagram of a computing system1000 embodiment in accordance with an embodiment. Shown in FIG. 6 is amultiprocessor system 1000 that includes a first processing element 1070and a second processing element 1080. While two processing elements 1070and 1080 are shown, it is to be understood that an embodiment of thesystem 1000 may also include only one such processing element.

The system 1000 is illustrated as a point-to-point interconnect system,wherein the first processing element 1070 and the second processingelement 1080 are coupled via a point-to-point interconnect 1050. Itshould be understood that any or all of the interconnects illustrated inFIG. 6 may be implemented as a multi-drop bus rather than point-to-pointinterconnect.

As shown in FIG. 6, each of processing elements 1070 and 1080 may bemulticore processors, including first and second processor cores (i.e.,processor cores 1074 a and 1074 b and processor cores 1084 a and 1084b). Such cores 1074 a, 1074 b, 1084 a, 1084 b may be configured toexecute instruction code in a manner similar to that discussed above inconnection with FIG. 5.

Each processing element 1070, 1080 may include at least one shared cache1896 a, 1896 b. The shared cache 1896 a, 1896 b may store data (e.g.,instructions) that are utilized by one or more components of theprocessor, such as the cores 1074 a, 1074 b and 1084 a, 1084 b,respectively. For example, the shared cache 1896 a, 1896 b may locallycache data stored in a memory 1032, 1034 for faster access by componentsof the processor. In one or more embodiments, the shared cache 1896 a,1896 b may include one or more mid-level caches, such as level 2 (L2),level 3 (L3), level 4 (L4), or other levels of cache, a last level cache(LLC), and/or combinations thereof.

While shown with only two processing elements 1070, 1080, it is to beunderstood that the scope of the embodiments are not so limited. Inother embodiments, one or more additional processing elements may bepresent in a given processor. Alternatively, one or more of processingelements 1070, 1080 may be an element other than a processor, such as anaccelerator or a field programmable gate array. For example, additionalprocessing element(s) may include additional processors(s) that are thesame as a first processor 1070, additional processor(s) that areheterogeneous or asymmetric to processor a first processor 1070,accelerators (such as, e.g., graphics accelerators or digital signalprocessing (DSP) units), field programmable gate arrays, or any otherprocessing element. There can be a variety of differences between theprocessing elements 1070, 1080 in terms of a spectrum of metrics ofmerit including architectural, micro architectural, thermal, powerconsumption characteristics, and the like. These differences mayeffectively manifest themselves as asymmetry and heterogeneity amongstthe processing elements 1070, 1080. For at least one embodiment, thevarious processing elements 1070, 1080 may reside in the same diepackage.

The first processing element 1070 may further include memory controllerlogic (MC) 1072 and point-to-point (P-P) interfaces 1076 and 1078.Similarly, the second processing element 1080 may include a MC 1082 andP-P interfaces 1086 and 1088. As shown in FIG. 6, MC's 1072 and 1082couple the processors to respective memories, namely a memory 1032 and amemory 1034, which may be portions of main memory locally attached tothe respective processors. While the MC 1072 and 1082 is illustrated asintegrated into the processing elements 1070, 1080, for alternativeembodiments the MC logic may be discrete logic outside the processingelements 1070, 1080 rather than integrated therein.

The first processing element 1070 and the second processing element 1080may be coupled to an I/O subsystem 1090 via P-P interconnects 1076 1086,respectively. As shown in FIG. 6, the I/O subsystem 1090 includes P-Pinterfaces 1094 and 1098. Furthermore, I/O subsystem 1090 includes aninterface 1092 to couple I/O subsystem 1090 with a high performancegraphics engine 1038. In one embodiment, bus 1049 may be used to couplethe graphics engine 1038 to the I/O subsystem 1090. Alternately, apoint-to-point interconnect may couple these components.

In turn, I/O subsystem 1090 may be coupled to a first bus 1016 via aninterface 1096. In one embodiment, the first bus 1016 may be aPeripheral Component Interconnect (PCI) bus, or a bus such as a PCIExpress bus or another third generation I/O interconnect bus, althoughthe scope of the embodiments are not so limited.

As shown in FIG. 6, various I/O devices 1014 (e.g., speakers, cameras,sensors) may be coupled to the first bus 1016, along with a bus bridge1018 which may couple the first bus 1016 to a second bus 1020. In oneembodiment, the second bus 1020 may be a low pin count (LPC) bus.Various devices may be coupled to the second bus 1020 including, forexample, a keyboard/mouse 1012, communication device(s) 1026, and a datastorage unit 1019 such as a disk drive or other mass storage devicewhich may include code 1030, in one embodiment. The illustrated code1030 may implement the beacon blocks or the observation blocks of themethod 22 (FIG. 2), the method 30 (FIG. 3A) and/or the method 44 (FIG.3B), already discussed, and may be similar to the code 213 (FIG. 5),already discussed. Further, an audio I/O 1024 may be coupled to secondbus 1020 and a battery 1010 may supply power to the computing system1000.

Note that other embodiments are contemplated. For example, instead ofthe point-to-point architecture of FIG. 6, a system may implement amulti-drop bus or another such communication topology. Also, theelements of FIG. 6 may alternatively be partitioned using more or fewerintegrated chips than shown in FIG. 6.

Additional Notes and Examples

Example 1 may include a user-based system comprising an enclosureincluding a wearable form factor, a tissue conduction speaker, a sensorincluding one or more of a tissue conduction microphone or anaccelerometer, an outbound signal controller to send, via the tissueconduction speaker, a sound wave signal, an inbound signal controllercoupled to the sensor, the inbound signal controller to measure a bodyconduction characteristic of the sound wave signal, and an authenticatorto perform a user authentication based at least in part on the bodyconduction characteristic.

Example 2 may include the system of Example 1, wherein the bodyconduction characteristic is to include one or more of a timing, afrequency or an amplitude of the sound wave signal after passing throughone or more of bone or tissue.

Example 3 may include the system of Example 1, wherein the authenticatorfurther includes one or more of a presence detector to detect a user; ora recognizer to identify the user.

Example 4 may include the system of Example 1, further including asupplemental factor component to perform the user authentication furtherbased on an additional authentication factor including one or more ofvoice input, gesture input or textual input.

Example 5 may include the system of Example 1, wherein the inboundsignal controller includes a sensor interface to capture, via thesensor, a measurement signal associated with the sound wave signal andcompare the measurement signal to a training signal.

Example 6 may include the system of any one of Examples 1 to 5, whereinthe outbound signal controller is to configure the sound wave signalbased on an expected user.

Example 7 may include the system of any one of Examples 1 to 5, whereinthe enclosure includes one of a single-part enclosure or a multi-partenclosure and wherein the wearable form factor includes one or more of aheadwear form factor, a wrist wear form factor or a hand wear formfactor.

Example 8 may include an authentication apparatus comprising an outboundsignal controller to send a sound wave signal, an inbound signalcontroller to measure a body conduction characteristic of the sound wavesignal, and an authenticator to perform a user authentication based atleast in part on the body conduction characteristic.

Example 9 may include the apparatus of Example 8, wherein the bodyconduction characteristic is to include one or more of a timing, afrequency or an amplitude of the sound wave signal after passing throughone or more of bone or tissue.

Example 10 may include the apparatus of Example 8, wherein theauthenticator further includes one or more of a presence detector todetect a user; or a recognizer to identify the user.

Example 11 may include the apparatus of Example 8, further including asupplemental factor component to perform the user authentication furtherbased on an additional authentication factor including one or more ofvoice input, gesture input or textual input.

Example 12 may include the apparatus of Example 8, wherein the inboundsignal controller includes a sensor interface to capture, via one ormore of a tissue conduction microphone or an accelerometer, ameasurement signal associated with the sound wave signal and compare themeasurement signal to a training signal, and wherein outbound signalcontroller is to send the sound wave signal via a tissue conductionspeaker.

Example 13 may include the apparatus of any one of Examples 8 to 12,wherein the outbound signal controller is to configure the sound wavesignal based on an expected user.

Example 14 may include a method of operating an authenticatingapparatus, comprising sending a sound wave signal, measuring a bodyconduction characteristic of the sound wave signal, and performing auser authentication based at least in part on the body conductioncharacteristic.

Example 15 may include the method of Example 14, wherein the bodyconduction characteristic includes one or more of a timing, a frequencyor an amplitude of the sound wave signal after passing through one ormore of bone or tissue.

Example 16 may include the method of Example 14, wherein performing theuser authentication includes one or more of detecting a user oridentifying the user.

Example 17 may include the method of Example 14, wherein the userauthentication is performed further based on an additionalauthentication factor including one or more of voice input, gestureinput or textual input.

Example 18 may include the method of Example 14, further includingcapturing, via one or more of a tissue conduction microphone or anaccelerometer, a measurement signal associated with the sound wavesignal; and comparing the measurement signal to a training signal,wherein the sound wave signal is sent via a tissue conduction speaker.

Example 19 may include the method of any one of Examples 14 to 18,further including configuring the sound wave signal based on an expecteduser.

Example 20 may include at least one computer readable storage mediumcomprising a set of instructions which, when executed by a computingdevice, cause the computing device to send a sound wave signal, measurea body conduction characteristic of the sound wave signal, and perform auser authentication based at least in part on the body conductioncharacteristic.

Example 21 may include the at least one computer readable storage mediumof Example 20, wherein the body conduction characteristic is to includeone or more of a timing, a frequency or an amplitude of the sound wavesignal after passing through one or more of bone or tissue.

Example 22 may include the at least one computer readable storage mediumof Example 20, wherein the instructions, when executed, cause acomputing device to one or more of detect a user to perform the userauthentication; or identify the user to perform the user authentication.

Example 23 may include the at least one computer readable storage mediumof Example 20, wherein the user authentication is to be performedfurther based on an additional authentication factor including one ormore of voice input, gesture input or textual input.

Example 24 may include the at least one computer readable storage mediumof Example 20, wherein the instructions, when executed, cause acomputing device to capture, via one or more of a tissue conductionmicrophone or an accelerometer, a measurement signal associated with thesound wave signal; and compare the measurement signal to a trainingsignal, wherein the sound wave signal is to be sent via a tissueconduction speaker.

Example 25 may include the at least one computer readable storage mediumof any one of Examples 20 to 24, wherein the instructions, whenexecuted, cause a computing device to configure the sound wave signalbased on an expected user.

Example 26 may include an authentication apparatus comprising means forperforming the method of any of Examples 14 to 19, in any combination orsub-combination thereof.

Thus, techniques described herein may provide a convenient, low powersolution to user authentication. Additionally, techniques may be moresecure due to the difficulty of observing and/or duplicating bodyconduction characteristics by unauthorized individuals. The techniquesmay be suitable in situations when user awareness of the authenticationprocess is not desired (e.g., background/stealth authentication) and/orthe user is not awake/unconscious (e.g., in public health scenarios).

Embodiments are applicable for use with all types of semiconductorintegrated circuit (“IC”) chips. Examples of these IC chips include butare not limited to processors, controllers, chipset components,programmable logic arrays (PLAs), memory chips, network chips, systemson chip (SoCs), SSD/NAND controller ASICs, and the like. In addition, insome of the drawings, signal conductor lines are represented with lines.Some may be different, to indicate more constituent signal paths, have anumber label, to indicate a number of constituent signal paths, and/orhave arrows at one or more ends, to indicate primary information flowdirection. This, however, should not be construed in a limiting manner.Rather, such added detail may be used in connection with one or moreexemplary embodiments to facilitate easier understanding of a circuit.Any represented signal lines, whether or not having additionalinformation, may actually comprise one or more signals that may travelin multiple directions and may be implemented with any suitable type ofsignal scheme, e.g., digital or analog lines implemented withdifferential pairs, optical fiber lines, and/or single-ended lines.

Example sizes/models/values/ranges may have been given, althoughembodiments are not limited to the same. As manufacturing techniques(e.g., photolithography) mature over time, it is expected that devicesof smaller size could be manufactured. In addition, well knownpower/ground connections to IC chips and other components may or may notbe shown within the figures, for simplicity of illustration anddiscussion, and so as not to obscure certain aspects of the embodiments.Further, arrangements may be shown in block diagram form in order toavoid obscuring embodiments, and also in view of the fact that specificswith respect to implementation of such block diagram arrangements arehighly dependent upon the computing system within which the embodimentis to be implemented, i.e., such specifics should be well within purviewof one skilled in the art. Where specific details (e.g., circuits) areset forth in order to describe example embodiments, it should beapparent to one skilled in the art that embodiments can be practicedwithout, or with variation of, these specific details. The descriptionis thus to be regarded as illustrative instead of limiting.

The term “coupled” may be used herein to refer to any type ofrelationship, direct or indirect, between the components in question,and may apply to electrical, mechanical, fluid, optical,electromagnetic, electromechanical or other connections. In addition,the terms “first”, “second”, etc. may be used herein only to facilitatediscussion, and carry no particular temporal or chronologicalsignificance unless otherwise indicated.

As used in this application and in the claims, a list of items joined bythe term “one or more of” may mean any combination of the listed terms.For example, the phrases “one or more of A, B or C” may mean A; B; C; Aand B; A and C; B and C; or A, B and C.

Those skilled in the art will appreciate from the foregoing descriptionthat the broad techniques of the embodiments can be implemented in avariety of forms. Therefore, while the embodiments have been describedin connection with particular examples thereof, the true scope of theembodiments should not be so limited since other modifications willbecome apparent to the skilled practitioner upon a study of thedrawings, specification, and following claims.

We claim:
 1. A system comprising: an enclosure including a wearable formfactor; a tissue conduction speaker; a sensor including one or more of atissue conduction microphone or an accelerometer; an outbound signalcontroller to send, via the tissue conduction speaker, a sound wavesignal; an inbound signal controller coupled to the sensor, the inboundsignal controller to measure a body conduction characteristic of thesound wave signal; and an authenticator to perform a user authenticationbased at least in part on the body conduction characteristic.
 2. Thesystem of claim 1, wherein the body conduction characteristic is toinclude one or more of a timing, a frequency or an amplitude of thesound wave signal after passing through one or more of bone or tissue.3. The system of claim 1, wherein the authenticator further includes oneor more of: a presence detector to detect a user; or a recognizer toidentify the user.
 4. The system of claim 1, further including asupplemental factor component to perform the user authentication furtherbased on an additional authentication factor including one or more ofvoice input, gesture input or textual input.
 5. The system of claim 1,wherein the inbound signal controller includes a sensor interface tocapture, via the sensor, a measurement signal associated with the soundwave signal and compare the measurement signal to a training signal. 6.The system of claim 1, wherein the outbound signal controller is toconfigure the sound wave signal based on an expected user.
 7. The systemof claim 1, wherein the enclosure includes one of a single-partenclosure or a multi-part enclosure and wherein the wearable form factorincludes one or more of a headwear form factor, a wrist wear form factoror a hand wear form factor.
 8. An apparatus comprising: an outboundsignal controller to send a sound wave signal; an inbound signalcontroller to measure a body conduction characteristic of the sound wavesignal; and an authenticator to perform a user authentication based atleast in part on the body conduction characteristic.
 9. The apparatus ofclaim 8, wherein the body conduction characteristic is to include one ormore of a timing, a frequency or an amplitude of the sound wave signalafter passing through one or more of bone or tissue.
 10. The apparatusof claim 8, wherein the authenticator further includes one or more of: apresence detector to detect a user; or a recognizer to identify theuser.
 11. The apparatus of claim 8, further including a supplementalfactor component to perform the user authentication further based on anadditional authentication factor including one or more of voice input,gesture input or textual input.
 12. The apparatus of claim 8, whereinthe inbound signal controller includes a sensor interface to capture,via one or more of a tissue conduction microphone or an accelerometer, ameasurement signal associated with the sound wave signal and compare themeasurement signal to a training signal, and wherein outbound signalcontroller is to send the sound wave signal via a tissue conductionspeaker.
 13. The apparatus of claim 8, wherein the outbound signalcontroller is to configure the sound wave signal based on an expecteduser.
 14. A method comprising: sending a sound wave signal; measuring abody conduction characteristic of the sound wave signal; and performinga user authentication based at least in part on the body conductioncharacteristic.
 15. The method of claim 14, wherein the body conductioncharacteristic includes one or more of a timing, a frequency or anamplitude of the sound wave signal after passing through one or more ofbone or tissue.
 16. The method of claim 14, wherein performing the userauthentication includes one or more of detecting a user or identifyingthe user.
 17. The method of claim 14, wherein the user authentication isperformed further based on an additional authentication factor includingone or more of voice input, gesture input or textual input.
 18. Themethod of claim 14, further including: capturing, via one or more of atissue conduction microphone or an accelerometer, a measurement signalassociated with the sound wave signal; and comparing the measurementsignal to a training signal, wherein the sound wave signal is sent via atissue conduction speaker.
 19. The method of claim 14, further includingconfiguring the sound wave signal based on an expected user.
 20. Atleast one computer readable storage medium comprising a set ofinstructions which, when executed by a computing device, cause thecomputing device to: send a sound wave signal; measure a body conductioncharacteristic of the sound wave signal; and perform a userauthentication based at least in part on the body conductioncharacteristic.
 21. The at least one computer readable storage medium ofclaim 20, wherein the body conduction characteristic is to include oneor more of a timing, a frequency or an amplitude of the sound wavesignal after passing through one or more of bone or tissue.
 22. The atleast one computer readable storage medium of claim 20, wherein theinstructions, when executed, cause a computing device to one or more of:detect a user to perform the user authentication; or identify the userto perform the user authentication.
 23. The at least one computerreadable storage medium of claim 20, wherein the user authentication isto be performed further based on an additional authentication factorincluding one or more of voice input, gesture input or textual input.24. The at least one computer readable storage medium of claim 20,wherein the instructions, when executed, cause a computing device to:capture, via one or more of a tissue conduction microphone or anaccelerometer, a measurement signal associated with the sound wavesignal; and compare the measurement signal to a training signal, whereinthe sound wave signal is to be sent via a tissue conduction speaker. 25.The at least one computer readable storage medium of claim 20, whereinthe instructions, when executed, cause a computing device to configurethe sound wave signal based on an expected user.